For weeks, hard-line elements in Iran's government have been calling
for the arrest of the country's opposition leaders, especially
defeated presidential candidates Mir-Hossein Mousavi and Mehdi
Karroubi. Now it appears that the government has raised the ante. On
Sept. 8, Iranian authorities raided offices connected to the two men
and arrested top opposition aides.

In particular, Tehran appears to have targeted the opposition's ongoing strategy of charging the government with abusing the
opposition demonstrators who were detained in the violence that followed Iran's contested presidential election in June. Security forces raided offices
belonging to Karroubi  who has led the effort to collect
evidence of abuse by security forces  and confiscated documents
related to the charges. (See pictures of people around the world protesting Iran's election.)

The raids are a measure of just how sensitive and damaging the claims of prisoner abuse have been for the Iranian government of President
Mahmoud Ahmadinejad. Of all the charges leveled against his administration by opposition leaders since the election  including widespread electoral fraud and staging a coup d'état  none has been as sickly captivating to Iranians as the
stories of abuse and torture that have trickled out from behind prison
walls. Not only is sexual violence particularly abhorrent in
conservative Iranian society, but the charges also challenge
the legitimacy of the Islamic government by calling into question its
foundation upon moral justice. The Islamic revolution was inspired in
part by such abuse during the Shah's authoritarian rule. (See pictures of terror in Tehran.)

Though pressure from the rape and torture charges sparked a promise by
Supreme Leader Ayatullah Ali Khamenei to bring any abusers to justice,
the government is now, evidently, pushing back. A parliamentary committee that heard the evidence of abuse collected by the opposition summarily dismissed the charges last week, but two men who jointly presented the
claims on behalf of the opposition  top Karroubi aid Morteza Alviri and top Mousavi aid Ali Reza Behesti  were arrested in the raids on Tuesday. The editor of Karroubi's website, which has also showcased
the abuse allegations, was also arrested. The day before, authorities raided
an office run by a Mousavi aide that recently said it had documented the
deaths of 72 protesters in the weeks-long protests that shook the capital.
(Authorities say 41 people, including security personnel, died during the
prolonged crackdown after
Ahmadinejad's disputed election victory, though human-rights groups
put the number in the hundreds.)

The latest crackdown demonstrates that the split between Iranian clerical leadership is only
deepening, and how, despite the government's tight controls over public
demonstrations, it remains wary of further dissent. The government has
canceled or downsized celebrations for the Muslim holy month of
Ramadan lest they become a platform for opposition
protests. On Sept. 6, reformist former President Mohammed Khatami decried these and other
"fascist" methods being deployed by the government. Just how much
longer the government will allow opposition leaders to make such comments
remains to be seen.